Today's Boy Genius BlackBerry Pearl (8100) leak: the User Guide and a good long look at the trackball that gives the Pearl its name. From the guide it looks like it has built-in support for Push-to-Talk, which Cingular will most likely take advantage of when it releases the Pearl later on the year. The Boy Genius also confirmed to us that the Cingular version will have cosmetically differences from the T-Mobile release. Boy Genius also sent us a video of the Pearl's trackball -- a setting in the phone app enables the trackball to changes colors to a ringtone set and during a phonecall.